US4559091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing hyperabrupt doping profiles in semiconductors
Assignee: University of California
•
Filing: 1984-06-15
•
Granted: 1985-12-17
•
Expires: 2004-06-15
Abstract
Abstract A method for achieving extreme and arbitrary doping profiles in semiconductors with dopant concentrations varying over orders of magnitude in a few atomic layers. The method involves evaporating the semiconductor, along with the desired amounts of n- or p- dopants onto an atomically clean substrate semiconductor surface in an ultrahigh vacuum environment at low temperatures such that an amorphous film results. The amorphous film is then crystallized epitaxially by a solid phase epitaxy, thereby providing a single crystal with the desired dopant profile. Multiple profile changes or grading may be included in the semiconductor film by varying dopant concentrations in the amorphous layer as desired.
Inventors
- 👤 Frederick G. Allen
- 👤 Dwight C. Streit
- 👤 Robert A. Metzger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:26
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/22; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/3438; H10P14/3441; H10P14/3442; H10P14/3444; H10P95/00; H10P95/90; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/925; Y10S438/936
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
62 words
A method for producing arbitrary doping profiles in a semiconductor, comprising: simultaneously depositing an amorphous layer of a semiconductor and a dopant onto an atomically clean semiconductor substrate; and epitaxially crystallizing said amorphous layer to produce an epitaxial film on said substrate, with the doping profile of said epitaxial film being determined by the concentration of said dopant in said amorphous layer.
Claim 2
Independent Claim
62 words
A method for producing arbitrary doping profiles in a semiconductor, comprising: simultaneously depositing an amorphous layer of a semiconductor and a dopant onto an atomically clean semiconductor substrate; and epitaxially crystallizing said amorphous layer to produce an epitaxial film on said substrate, with the doping profile of said epitaxial film being determined by the concentration of said dopant in said amorphous layer.
Claim 3
Independent Claim
83 words
A method for producing hyperabrupt doping profiles in semiconductors, comprising: cleaning a substrate semiconductor surface on an atomic scale; depositing a semiconductor film in an amorphous form onto said substrate, thereby producing a growing amorphous layer; co-depositing a dopant in said amorphous layer as said layer is growing; and epitaxially crystallizing said amorphous layer to produce an epitaxial film, whereby an epitaxial film is produced on said substrate with the doping profile in said film being determined by the concentration of said dopant.
Claim 4
Independent Claim
83 words
A method for producing hyperabrupt doping profiles in semiconductors, comprising: cleaning a substrate semiconductor surface on an atomic scale; depositing a semiconductor film in an amorphous form onto said substrate, thereby producing a growing amorphous layer; co-depositing a dopant in said amorphous layer as said layer is growing; and epitaxially crystallizing said amorphous layer to produce an epitaxial film, whereby an epitaxial film is produced on said substrate with the doping profile in said film being determined by the concentration of said dopant.
Claim 5
Dependent Claim
50 words
A method as defined in claim 2, wherein said method comprises the additional step of: minimizing unwanted impurities in said amorphous layer by maintaining a high ratio between the incident flux rate of said semiconductor and that of any ambient gas present during said depositing step and said co-depositing step.
Claim 6
Independent Claim
19 words
A method as defined in claims 1 or 2, wherein: said method is performed in an ultrahigh vacuum environment.
Claim 7
Independent Claim
25 words
A method as defined in claims 1 or 2, wherein: said method is performed in an environment having a pressure less than 10 -10 Torr.
Claim 8
Independent Claim
31 words
A method as defined in claims 1 or 2, wherein: said step of depositing is performed with said substrate being held at a temperature below that at which epitaxial growth occurs.
Claim 9
Independent Claim
19 words
A method as defined in claims 1 or 2, wherein said step of crystallizing comprises: solid phase epitaxial regrowing.
Claim 10
Independent Claim
25 words
A method as defined in claims 1 or 2, wherein: said step of crystallizing is performed at a temperature in the range of 500°-600° C.
Claim 11
Independent Claim
47 words
A method as defined in claims 1 or 2 wherein said method comprises the additional step of: minimizing unwanted impurities in said amorphous layer by maintaining a high ratio between the incident flux rate of said semiconductor and any ambient gas present during said step of depositing.
Claim 12
Dependent Claim
34 words
A method as defined in claim 1, wherein: said step of depositing includes the preliminary step of cleaning said surface of said semiconductor substrate on an atomic scale to permit subsequent defect-free epitaxial growth.
Claim 13
Dependent Claim
36 words
A method as defined in claim 1, wherein: said step of simultaneously depositing includes the step of effecting a plurality of changes in said profile by varying the concentration of the dopant in said amorphous layer.
References Cited (Backward Citations)
US2841509A
Cited
US2841559A
Cited
US2809165A
Cited
US3036898A
Cited
US3459152A
Cited
US3442775A
Cited
US3600242A
Cited
US3669769A
Cited
US3765940A
Cited
US4012235A
Cited
US4270960A
Cited
US4226648A
Cited
US4319954A
Cited
US4402762A
Cited
US4485128A
Cited
US4509990A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-16 | 1989-06-17 | 1989-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-16 | 1993-06-17 | 1993-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-16 | 1997-06-17 | 1997-12-17 | $7700.00 | Window Closed / Lapsed |